Lamb waves and shear horizontal (SH) waves are used in guided wave non-destructive evaluation (NDE). Lamb waves and SH waves have different propagation characteristics and sensitivities to different defects. It is beneficial to employ both wave types to accommodate to different working conditions and improve sensitivities to various defects.
Electro-magnetic acoustic transducers (EMATs) are used in industrial NDE because of their non-contact feature. EMATs for Lamb and SH wave excitation typically have distinctive designs such that one EMAT can only excite one type of wave. This restriction imposes limitations on the overall performance and applicability of such EMATs.